Sounds like you have a fair idea of what you want to do when you leave school.

While you lack experience in the retail environment specifically, your hospitality background would have taught you some great customer service skills. This gives you a great opportunity to really draw attention to this fact in interviews. For example, you may be asked about a time when you had a difficult customer and how you overcame this-here you could really talk up your problem solving skills and emphasise how you are able to deal with all different kinds of customers.

Additionally, be sure to have thought about what you believe your biggest strengths and weaknesses are, employers regularly ask this in interviews. Don't just simply state these however, explain to the employer how you believe your strengths can benefit their organisation.

In terms of personal presentation, make sure you are very tidy and don't forget to remain somewhat relaxed to allow your personality to shine through.